This is a Phase II study to look at the effects of the investigational drug DMP 754 which has potential potent effects on platelet aggregation. This protocol consisted of eight parts, of which we participated in four. DMP 754 was studied in the following doses: 0.25 mg, 0.5 mg, 0.75 mg, 1.0 mg, 1.25 mg, 1.5 mg, 2.0 mg or 2.5 mg daily for up to 30 days. Endpoints include tolerability and safety and also effectiveness in inhibiting platelets as assessed by platelet aggregation studies. There were two IND safety reports submitted to the FDA that were thought to be study drug related. Both reports resulted from severe thrombocytopenia in two individual subjects. Minor adverse events included bleeding gums and nose bleeds which were not clinically significant. There were 51 participants in this study which was completed February 1998. The protocol was reactivated for a patient who had developed severe thrombocytopenia. This patient had continued involvement in this study via a service agreement with DuPont Pharmaceuticals Company. The service agreement involved blood draws only. This patient has concluded this agreement. This study has resulted in an abstract to be submitted to the American Heart Association in May 1999 for presentation November 1999 with manuscript to follow. Mayo investigators will be the primary authors on this manuscript and abstract.